The embodiments herein relate generally to machines that are used to move users below a ground surface in a bridge construction setting.
Prior to embodiments of the disclosed invention, machines existed that could move users below a ground surface, but those machines only operated on solid level ground. Some examples of these efforts include: U.S. Pat. Nos. 5,253,373, 5,318,149 and 4,696,371 all issued to Moog; U.S. Pat. No. 4,154,318 issued to Malleone, Chinese Patent 2,761,682 issued to Sun; UK Patent 1,515,114 issued to Harrison; UK Patent 1,321,051 issued to Bartoli; and Chinese Patent 102,071,638 issued to Hao.